People that are farsighted due to old age or people that are weak-sighted may sometimes use reading glasses or magnifying glasses for visually recognizing characters more easily. However, the use of reading glasses or magnifying glasses is troublesome. Further, reading glasses and magnifying glasses are inconvenient to carry.
Owing to the wide use of smartphones in recent years, electronic devices such as smartphones are equipped with a function of a magnifying glass or a reading glass. For example, an enlarged moving image can be obtained by photographing an object with a camera of a smartphone and displaying a predetermined portion of the photographed object.
Further, Patent Document 1 proposes a technique of preparing a handout for a presentation by using a document preparation apparatus. The handout is prepared by automatically editing only the contents of a necessary area of a regular original document and converting the characters or diagrams of the edited contents into a viewable size.